Heat-treating furnace



July 29, 1930. J. LUNDBORG HEAT TREATING FURNACE OriginaLFiled Oct. 31, 1928 [NVENTDR JUSEF LLINDBDRG BY jw' ATTORNEY Patented n, 29, 1930 UNITED STATES PATENT: OFFICE Josnr mmmsone, or 'roLEno, OHIO, ASSIGNOR ro 'rnn sum-eon ooms'osrron co.,

moonrom'rnn, or TOLEDO, 01:10, A conrona'rron" on NEW roux HEAT-TREATING FURNACE Application filed ctober31, 1928, Serial No. 316,178. Renewed April 2, 1930.

This invention relates to improvements in heat-treating furnaces and has as its general I object to' provide an improved movablehe'arth type of furnace. More particularl it "5 is anobject of the invention to provide at urnaceof annular form having an endless heating chamber wherein is mounted a rotary annular tray or hearth so arranged that it may be heatedfrom below as well as from above and rotated in a series of steps. 7

Referring to the drawings wherein the'preferredform of the invention is shown:

Fig. 1 is a plan view of theimproved furnace, a portion thereof being broken away, is and I .Fig. 2 furnace. Suitably supported by a frame work 10 is 1 an annular furnace structure forming a heating chamber 12. Supported'o'n and rising from the floor 14 of-the chainber are two concentric rows-of piers or hearth supports 16. :Supported on the piersis an annular hearth or tray '18 of suitable heat-resisting metal.

Positioned. in the opposite side walls' of'the heating chamber and firin into the chamber below the hearth are gas fiurners 20 and 22,

the burners being in staggered relation and I firing through the radially extending spaces ac '24 between the piers wherebythe hot gases pass under the hearth and up along the op-- posite side wall and into the top portion of the chamber above the hearth, the latter being of less width than the chamber. Similar burners 26 and-28 ma also be positioned in:

the chamber side wal s at alevelabove the hearth to fire directly into the top portion of the chamber. I

. In the outer side wall of the heating chamher are suitable openings through which the work to be heat-treated may be enteredinto and removed from the chamber, the openings being closed by suitable doors 30 and 32.

In the fioor of the chamber between thepiers are circumferentially spaced arcuate openings 34 wherein are positioned movable upright posts 36 which at theirlower ends are secured to the ends of radial arms 38 secured to an upright shaft 40 positioned at no the axis of the furnace in suitable bearings is a vertical section through-the 42 and 44. The lower end of. the shaft is stepped in a bearing 46 mounted on a horizontally disposed lever 48 pivoted at one end to a support'50 and connected at itsother end with an upright link 52. The upper end of this link is connected to a crank arm 54 on the shaft of a speed reducing mechanism .56.

which in turn is driven by a motor 58. vRotation of the crankshaft raises and lowers the shaft 40 and hence the posts 36as will now dividual posts 36 is such that w en the shaft 40 is at its lowermost position the tops of the osts 36 are out of contact with the hearth 18 at when the shaft is raised the posts engage 'an arm to the outer end of which is connected a link 62 which in turn is connected. to a crank'arm 64 on the shaft .of a speed reducing mechanism-66 driven by a-motor 68.

For each complete revolution of the crank-- shaft, the shaft 40 is given a forward and backward rotation, the motors 58 and 68 being so synchronized that when the shaft 40 has been elevated to lift the hearth the shaft isgiven a forward rotation and vice versa as will now be readily understood. The hearth is. therefore,' advanced in a series of steps.

The bottom of the floor openings through which the posts 36 pass are sealed by plates. 7 0 through which the posts pass,.the plates being movable with the posts and slidably mounted below the floor opening as will be readily understood. There'is no stack con- :necting with the heating chamber, and con--.

sequently there is a plenum of gases within I so be readily understood. The len h of the inthe heating chamber which tends'to prevent the entry ofair into the heating chamber.

By supporting and moving the hearth as shown and described the hearth and consequently the work resting thereon may be thoroughly heated from below as well as from above and the furnace as a whole constructed at low cost.

- What is claimed is:

1. In a furnace, the combination of means forming an annular heating tunnel, an annular hearth within the tunnel, piers extendin upwardly from the floor of the'tnnnel an adapted to support the hearth, and means adapted to raise the hearth from said piers and impart a rotary movement thereto. 7.

2. In a furnace, the combination of means 0 forming an annular heatin tunnel, an annuv lar hearth within the tunne an upright shaft at the axis of the tunnel, radial arms secured to the shaft and terminating below the floor of the tunnel, upright posts at the outer ends of said arms, said posts projecting through the floor of thetunnel and adapted to take the burden of the hearth, and means for periodically elevating and imparting a rotary motion" to said shaft.

3. In, an annular heating furnace, a rotatable tray within said furnace, a vertically disposed shaft at'the axis of the furnace, a bearing in which said shaft is stepped, means for elevating said bearing to elevate the shaft,

i5 means for turning said shaft, and means connected to said shaft for elevating and turning said tray as'the shaft is elevated and turned.

4. In apparatus of thecharacter described, the combination of a flat annular tray, a heat ing chamber wherein said tray is positioned, the bottom of said chamber being provided with a series of circumferentially spaced slots, upright posts individual to each slot, a

' common support for said posts, and means for vertically and horizontally reciprocating said support whereby the tray may be given a step by step rotation.

5. In apparatus of the character described,

, the combination of a flat annular tray, a heat 40 ing chamber wherein said tray is positioned,

the bottom of said chamber being provided with a series of circumferentially spaced slots, means rising from the bottom of said chamber for supporting said tray thereabove, upright posts individual to each slot, a common support'for said posts, and means for vertically and horizontally reciprocating said support whereby the tray may be given a step by step rotation; j

In testimony whereof I aflix my signature.

' J OSEF LUNDBORG 

